Curable composition of a polyepoxide with a methylol derivative of a polythiol

Abstract

Formaldehyde is reacted with a polythiol to give novel methylol derivatives of the polythiol. The methylol derivatives are useful in curing polyepoxides.

What is claimed is: 
     
       1. A curable composition comprising a 1,2-polyepoxide in admixture with a methylol derivative of a polythiol having the formula: ##SPC6## wherein n is 1-3, one of R and R' is hydrogen and the other is hydrogen or methyl, and R" is hydrogen or methyl; or said derivative having the formula ##SPC7##   wherein each R is --Cl, --Br, --SR 1  SY or --OR 2  SR 1  SY provided that at least two of said R groups independently are of said --SR 1  SY or --OR 2  SR 1  SY; R 1  is an alkylene group having 2 to 10 carbon atoms or an alkylene group having 2 to 10 carbon atoms having one or more --O-- or --S-- ether groups and R 2  is an alkylene group of 2 to 4 carbon atoms; and wherein at least one Y is --CH 2  OH.   
     
     
       2. The curable composition of claim 1 wherein said methylol derivative has from 5 to 100 percent of the thiol groups substituted with methylol. 
     
     
       3. The curable composition of claim 2 further comprising an auxiliary epoxy resin curing agent. 
     
     
       4. The curable composition of claim 3 wherein said auxiliary curing agent is benzyldimethylamine. 
     
     
       5. A cured product resulting from the reaction of a 1,2-polyepoxide with a methylol derivative of a polythiol having the formula: ##SPC8## wherein n is 1-3, one of R and R' is hydrogen and the other is hydrogen or methyl, and R" is hydrogen or methyl; or said derivative having the formula ##SPC9##   wherein each R is --Cl, --Br, --SR 1  SY or --OR 2  SR 1  SY provided that at least two of said R groups independently are of said --SR 1  SY or --OR 2  SR 1  SY; R 1  is an alkylene group having 2 to 10 carbon atoms or an alkylene group having 2 to 10 carbon atoms having one or more --O-- or --S-- ether groups and R 2  is an alkylene group of 2 to 4 carbon atoms; and wherein at least one Y is --CH 2  OH.   
     
     
       6. The cured product of claim 5 wherein said 1,2-polyepoxide is the diglycidyl ether of bisphenol A.